/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.runtime.rest.handler.job.coordination;

import org.apache.flink.api.common.JobID;
import org.apache.flink.api.common.time.Time;
import org.apache.flink.runtime.jobgraph.OperatorID;
import org.apache.flink.runtime.operators.coordination.CoordinationRequest;
import org.apache.flink.runtime.operators.coordination.CoordinationResponse;
import org.apache.flink.runtime.rest.handler.AbstractRestHandler;
import org.apache.flink.runtime.rest.handler.HandlerRequest;
import org.apache.flink.runtime.rest.handler.RestHandlerException;
import org.apache.flink.runtime.rest.messages.JobIDPathParameter;
import org.apache.flink.runtime.rest.messages.MessageHeaders;
import org.apache.flink.runtime.rest.messages.OperatorIDPathParameter;
import org.apache.flink.runtime.rest.messages.job.coordination.ClientCoordinationMessageParameters;
import org.apache.flink.runtime.rest.messages.job.coordination.ClientCoordinationRequestBody;
import org.apache.flink.runtime.rest.messages.job.coordination.ClientCoordinationResponseBody;
import org.apache.flink.runtime.webmonitor.RestfulGateway;
import org.apache.flink.runtime.webmonitor.retriever.GatewayRetriever;
import org.apache.flink.util.SerializedValue;

import org.apache.flink.shaded.netty4.io.netty.handler.codec.http.HttpResponseStatus;

import javax.annotation.Nonnull;

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionException;

/**
 * Handler that receives the coordination requests from the client and returns the response from the coordinator.
 */
public class ClientCoordinationHandler extends AbstractRestHandler<RestfulGateway, ClientCoordinationRequestBody, ClientCoordinationResponseBody, ClientCoordinationMessageParameters> {

	public ClientCoordinationHandler(
			GatewayRetriever<? extends RestfulGateway> leaderRetriever,
			Time timeout,
			Map<String, String> responseHeaders,
			MessageHeaders<ClientCoordinationRequestBody, ClientCoordinationResponseBody, ClientCoordinationMessageParameters> messageHeaders) {
		super(leaderRetriever, timeout, responseHeaders, messageHeaders);
	}

	@Override
	protected CompletableFuture<ClientCoordinationResponseBody> handleRequest(
			@Nonnull HandlerRequest<ClientCoordinationRequestBody, ClientCoordinationMessageParameters> request,
			@Nonnull RestfulGateway gateway) throws RestHandlerException {
		JobID jobId = request.getPathParameter(JobIDPathParameter.class);
		OperatorID operatorId = request.getPathParameter(OperatorIDPathParameter.class);
		SerializedValue<CoordinationRequest> serializedRequest =
			request.getRequestBody().getSerializedCoordinationRequest();
		CompletableFuture<CoordinationResponse> responseFuture =
			gateway.deliverCoordinationRequestToCoordinator(jobId, operatorId, serializedRequest, timeout);
		return responseFuture.thenApply(
			coordinationResponse -> {
				try {
					return new ClientCoordinationResponseBody(new SerializedValue<>(coordinationResponse));
				} catch (IOException e) {
					throw new CompletionException(
						new RestHandlerException(
							"Failed to serialize coordination response",
							HttpResponseStatus.INTERNAL_SERVER_ERROR,
							e));
				}
			});
	}
}
